<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
	#box{
		width: 500px;
		height: 300px;
		border: 4px solid blue;
		/*color: green;*/
	}
	#title{
		font-size: 50px;
		color: blue;
	}
	h1{
		color: red;
	}
	
</style>
</head>

<body>

<!-- div#box>h1#title -->
<div id="box">
	我是box里面的文字
	<h1 id="title">后盾网 人人做后盾</h1>
</div>

<!-- css继承性：子元素会继承父元素的文字样式 -->
<!-- css叠加性：不同的选择给同一个元素加的样式能同时生效 -->

</body>
</html>
